1) Guantanamo
2) Waterboarding
3 things-
3) invading Afghanistan
I would add a fourth we may never know for sure
knocking off Saddam Hussein and his intelligence apparatchiks as a replacement for the Taliban in sponsoring and assisting al Qaeda
I gave those 2 because they were definite and incontrovertible.
ANy lib which claims obama did this needs to be given these 2 things obama fought strongly against with every fiber of his being.